/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.googlecode.jasperlib.internal.jasper.el;

import java.util.Iterator;

import javax.el.ArrayELResolver;
import javax.el.BeanELResolver;
import javax.el.CompositeELResolver;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ELResolver;
import javax.el.ListELResolver;
import javax.el.MapELResolver;
import javax.el.PropertyNotFoundException;
import javax.el.PropertyNotWritableException;
import javax.el.ResourceBundleELResolver;
import javax.servlet.jsp.el.VariableResolver;

public final class ELResolverImpl extends ELResolver {

    public final static ELResolver DefaultResolver = new CompositeELResolver();

    static {
        ((CompositeELResolver) DefaultResolver).add(new MapELResolver());
        ((CompositeELResolver) DefaultResolver).add(new ResourceBundleELResolver());
        ((CompositeELResolver) DefaultResolver).add(new ListELResolver());
        ((CompositeELResolver) DefaultResolver).add(new ArrayELResolver());
        ((CompositeELResolver) DefaultResolver).add(new BeanELResolver());
    }

    private final VariableResolver variableResolver;

    public ELResolverImpl(VariableResolver variableResolver) {
        this.variableResolver = variableResolver;
    }

    public Object getValue(ELContext context, Object base, Object property) throws NullPointerException,
            PropertyNotFoundException, ELException {
        if (context == null) {
            throw new NullPointerException();
        }

        if (base == null) {
            context.setPropertyResolved(true);
            if (property != null) {
                try {
                    return this.variableResolver.resolveVariable(property.toString());
                } catch (javax.servlet.jsp.el.ELException e) {
                    throw new ELException(e.getMessage(), e.getCause());
                }
            }
        }

        if (!context.isPropertyResolved()) {
            return DefaultResolver.getValue(context, base, property);
        }
        return null;
    }

    public Class<?> getType(ELContext context, Object base, Object property) throws NullPointerException,
            PropertyNotFoundException, ELException {
        if (context == null) {
            throw new NullPointerException();
        }

        if (base == null) {
            context.setPropertyResolved(true);
            if (property != null) {
                try {
                    Object obj = this.variableResolver.resolveVariable(property.toString());
                    return (obj != null) ? obj.getClass() : null;
                } catch (javax.servlet.jsp.el.ELException e) {
                    throw new ELException(e.getMessage(), e.getCause());
                }
            }
        }

        if (!context.isPropertyResolved()) {
            return DefaultResolver.getType(context, base, property);
        }
        return null;
    }

    public void setValue(ELContext context, Object base, Object property, Object value) throws NullPointerException,
            PropertyNotFoundException, PropertyNotWritableException, ELException {
        if (context == null) {
            throw new NullPointerException();
        }

        if (base == null) {
            context.setPropertyResolved(true);
            throw new PropertyNotWritableException("Legacy VariableResolver wrapped, not writable");
        }

        if (!context.isPropertyResolved()) {
            DefaultResolver.setValue(context, base, property, value);
        }
    }

    public boolean isReadOnly(ELContext context, Object base, Object property) throws NullPointerException,
            PropertyNotFoundException, ELException {
        if (context == null) {
            throw new NullPointerException();
        }

        if (base == null) {
            context.setPropertyResolved(true);
            return true;
        }

        return DefaultResolver.isReadOnly(context, base, property);
    }

    public Iterator<java.beans.FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
        return DefaultResolver.getFeatureDescriptors(context, base);
    }

    public Class<?> getCommonPropertyType(ELContext context, Object base) {
        if (base == null) {
            return String.class;
        }
        return DefaultResolver.getCommonPropertyType(context, base);
    }

}
